Quartz resonator of small dimensions

Abstract

The invention concerns a piezoelectric resonator ( 10 ), intended to be packaged in a case, including a base ( 12 ) formed of a first fixing zone ( 121 ), a second central mechanical uncoupling zone ( 122 ) and a third zone ( 123 ) opposite to the first fixing zone. At least two vibrating arms ( 13 a , 13 b ) extend from said third zone, on each of which at least one groove ( 141 a - 144 a , 141 b - 144 b ) is formed on at least one of the top or bottom faces of the arms. The resonator is characterised in that the base is provided with a hole ( 15 ) through the second central mechanical uncoupling zone.

What is claimed is: 
     
       1. A piezoelectric resonator, packaged in a case, including a base formed of a first fixing zone, a second central mechanical uncoupling zone and a third zone opposite to the first fixing zone, at least two vibrating arms extending from said third zone, on each of which at least one groove is formed on at least one of the top or bottom faces of the arms, wherein the base is provided with a hole through the second central mechanical uncoupling zone,
 and wherein said hole has a polygonal shape, at least two sides of which form an angle minimising the visualization of the crystalline planes during etching. 
 
     
     
       2. The piezoelectric resonator according to  claim 1 , wherein said first fixing zone of the base is fixed to the case by means of a rigid conductive agent. 
     
     
       3. The piezoelectric resonator according to  claim 2 , wherein the rigid conductive agent is an adhesive agent or a weld. 
     
     
       4. The piezoelectric resonator according to  claim 1 , wherein said hole has a length comprised between 33 and 75% of the width of the base. 
     
     
       5. The piezoelectric resonator according to  claim 1 , wherein said hole has a length comprised between 39 and 50% of the width of the base. 
     
     
       6. The piezoelectric resonator according to  claim 1 , wherein said hole has a width comprised between 10 and 50% of the length of the base. 
     
     
       7. The piezoelectric resonator according to  claim 1 , wherein said hole has a width comprised between 15 and 25% of the length of the base. 
     
     
       8. The piezoelectric resonator according to  claim 1 , wherein said third zone of the base has a width comprised between 50 and 200% of the width of an arm. 
     
     
       9. The piezoelectric resonator according to  claim 1 , wherein said third zone of the base has a width comprised between 80 and 130% of the width of an arm. 
     
     
       10. A piezoelectric resonator, packaged in a case, including a base formed of a first fixing zone, a second central mechanical uncoupling zone and a third zone opposite to the first fixing zone, at least two vibrating arms extending from said third zone, on each of which at least one groove is formed on at least one of the top or bottom faces of the arms, wherein the base is provided with a hole through the second central mechanical uncoupling zone, and
 wherein said hole has a polygonal shape the sides of which are cut so as to minimise the visualization of the crystalline planes of the piezoelectric resonator. 
 
     
     
       11. The piezoelectric resonator according to  claim 10 , wherein the resonator is formed by a quartz crystal and wherein the hole has a polygonal shape at least one angle of which has a value of 60 or 120°. 
     
     
       12. The piezoelectric resonator according to  claim 1 , wherein each arm includes two straight grooves on each of the bottom and top faces. 
     
     
       13. The piezoelectric resonator according to  claim 2 , wherein, where the arms are fixed, the third zone has a cut out portion minimising the visualization of the crystalline planes of the piezoelectric resonator. 
     
     
       14. The piezoelectric resonator according to  claim 13 , wherein the resonator is formed by a quartz crystal and wherein said cut out portion has an angle of 60 or 120°. 
     
     
       15. Vibrator including a case in which a piezoelectric resonator according to  claim 1 , is fixed, wherein a rigid conductive agent is used as means for fixing the case to the resonator. 
     
     
       16. The piezoelectric resonator according to  claim 1 , wherein said hole has an octagonal shape having 4 angles of 120° on the side of the lateral flanks of said base the resonator. 
     
     
       17. The piezoelectric resonator according to  claim 1 , wherein said hole has a hexagonal shape having 2 angles of 60° on the side of the lateral flanks of said base of the resonator. 
     
     
       18. The piezoelectric resonator according to  claim 1 , wherein said hole has a hexagonal shape having 6 angles of 120°.